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Matt, If alllll llll 3 terminals on that VR are reading hot battery voltage when shes not running as you indicate "with the key on" you got a serious VR problem, get a new one. Not running the ONLY VR terminal that should show hot battery voltage is the BAT terminal since it wires to the load (NOT to battery/starter) side of the ammeter. The VR"s ARM terminal wires to the Gennys Arm post and it shouldnt be showing any voltage not running cuz the cutout relay (relay between BAT and ARM on VR) should be open and the gennys not running to produce any voltage out its ARM post. The VR"s FLD post shouldnt be showing any battery voltage, its like a near dead short to ground. PS Its the Genny, NOT the VR that gets polarized. You asked how to test for a genny or a VR problem, heres how to determine which is at fault if shes not charging plus how to Motor Test the genny itslef to see if its good... TO DETERMINE IF ITS A GEN OR VR OR CUTOUT RELAY PROBLEM 5. a) VOLTAGE REGULATOR SYSTEM: With the tractor running, temporarily ground the Gens Field post to case. If she charges then but NOT otherwise, the VR may be bad, or a wires missing from VR"s Field post to the Field terminal on the VR, or the VR isn’t well grounded. b) IF IT’S A CUTOUT RELAY SYSTEM and she charges only if you dead ground the Field but NOT otherwise, its either a bad switch or the switch isn’t well grounded or else the wires bad or open from the Gens Field post up to the switch. INSURE THAT GOOD SWITCH GROUND AND WIRING 6. If she still don’t charge, leave the Field grounded and jump a wire across from the VR or Cutout Relays BAT terminal over to its GEN terminal (jump by passes the cutout relay) and see if she charges. If then but not otherwise, a VR"s cutout relay isn’t working correct (maybe points burned/carboned) or a Cutout Relays NOT working or not wired correct. 7. With the 2 steps above, you have basically by passed the VR or Cutout relays functions, so if she still don’t charge, you"re left with a bad battery or wiring or the Gen itself. 8. MOTOR TEST. You can Motor test the Gen. If its grounded and you remove the belt and apply hot battery voltage direct to its ARM Post and have the Field Post dead grounded to frame, it should motor n run well (Armature n Brushes and Commutator likely okay). Then, if you next remove the Fields ground and it speeds up some, the Fields probably good. If it passes both those tests, it should charge, and if not, it may be a wiring or battery or grounding problem. The hot battery voltage may be taken off the VR"s BAT terminal or the starter post or the battery itself for this test. John T
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